Which of the following statements is/are true? (A) $(\tan^{-1}y-x)dy = (1 + y^2)dx$ is a differential equation where variables are separable. Choose the correct answer from the options given below: |
(A) only (B) and (C) only (B) and (D) only (A), (B), (C) and (D) |
(B) and (C) only |
The correct answer is Option (2) → (B) and (C) only (A) False. Rewrite as $\frac{dy}{dx}=\frac{1+y^{2}}{\tan^{-1}y-x}$; variables are not separable (equation is linear in $x$ when viewed as $dx/dy$). (B) True. Rewrite as $\frac{dy}{dx}+\frac{2x}{1+x^{2}}\,y=\frac{\cot x}{1+x^{2}}$, a first-order linear ODE in $y$ (for $x\ne0$). (C) True. $ (4x+6y+5)\,dy-(3y+2x+4)\,dx=0$ contains nonzero constant terms (5,4), so the functions are not homogeneous of the same degree; hence not homogeneous. (D) False. $M(x,y)=xy$ is homogeneous of degree 2 but $N(x,y)=-(x+y^{2})$ is not homogeneous of the same degree, so the equation is not homogeneous. True statements: (B) and (C) |